Sorbonne students protesting today are the cause of the Paris riots by unemployed Muslims last year. Because firing costs are hiring costs. And that gives scope to selection by race. - Alex Tabarrok at Marginal Revolution

Nationals prefer the salaries and working conditions of government jobs -- most open only to them. And it is difficult to dismiss a national employee. Thus, firms are reluctant to hire nationals because they are likely to quit and because it is difficult to fire them. The citizens' rights create barriers to their employment.